Maybe is not related to this, but take a look here: REALTIME PRIORITY
If you don't play/upsample with Roon, but you are using Roon only as control point, it will not need an high realtime priority.
2) RTAPP configuration
Please read first the readme at /usr/share/doc/rtapp/readme.txt
The default configuration file is /etc/rtapp/rtapp.conf
APPLICATIONS="jackd mpd hqplayer hqplayerd RoonAppliance RoonBridge sox mediacenter24 networkaudiod deadbeef a2jmidid ardour-5.12.0 rosegarden audacity"
In general you don't need to modify the list of applications, but if you are using Roon as control point for HQPlayer, the real player would be the last one, so we suggest to remove RoonAppliance from that list. This is true in general if you are using one of the applications in the list only as a control point.